The present invention relates generally to locking devices for window sash, and more particularly, to a locking assembly which enables the balancing forces developed by the sash balance or other counterweight device to be temporarily locked against movement so that the window sash may be removed for cleaning, replacement or repair without altering the position of the sash balance or counterweight mechanism.
Assemblies of this general type are known to the prior art, but the present invention is directed to an improved form of assembly which includes novel features of construction and provides important advantages in operation. In the residential and commercial window field, it is of increasing importance to be able to remove or reposition window sash for cleaning, replacement and repair in a simple and straightforward manner, and in such a way that special equipment or skilled labor is not required.
With the ever increasing cost of maintenance and repair and labor, it is important that a window sash assembly, including one or more window jambs, jamb liners and balance assemblies, be of an integrated design such that the parts cooperate in use to provide the best combination of thermal insulation, low cost and convenience in use and wherein anticipated maintenance and repair costs are also low.
By way of background, the tendency of a window sash to fall by gravity to a lowered position, i.e., either closed or open, depending on whether it is an upper or a lower sash, is counteracted by some sort of balancing device. In the simpler systems, one or more springs are provided to offset a portion of the weight and the remainder of the "balancing" is accomplished in a relatively crude, but sometimes sufficiently effective way by providing sufficient engaging friction with the jamb or jamb liner to prevent the window sash from simply assuming a neutral position at which point the spring return forces exactly balance the weight load of the sash.
In more sophisticated systems, devices including block and tackle assemblies provide a combination of the necessary internal friction and mechanical advantage such that a relatively limited movement of the balance assembly provides a much larger range of movement of the sash itself, with springs also being included in these assemblies so as to provide the lifting or weight-offsetting force. In such constructions, the tendency of the sash to assume a single position is much more easily overcome, and a range of balancing forces readily permitting the window to remain balanced through a range of positions from fully open to fully closed is provided.
In the prior art, means of locking in place the window hardware affixed to the movable end of the balance assembly are also known, but these systems have suffered from one or more drawbacks, and are otherwise capable of improvement in use. The present invention is particularly concerned with a form of assembly directed to this end, and particularly to a construction wherein a sash support and movement lock assembly may be utilized successfully with an associated jamb liner extrusion of a single design, regardless of whether a more sophisticated sash balance is used, or simple balancing springs only are provided. The assembly of the invention includes a support for a sash mounting pivot which, upon limited rotation, actuates a cam which secures the lock and enables the sash to be removed while the lock and balance remain in place.
According to the invention, an adjustable friction brake element is also provided in the lock assembly which renders it adaptable for use with the simple spring-type balance. In this way, the amount of frictional drag intended to be imparted to the sash may be adjusted independently of the force required to lock the support assembly in place, and also independently of friction developed by the fit of the sash with the jamb liner. An undesirably tight fit or close interference between the dimensions of the facing parts respectively of the jamb liner and the window sash edges and/or weather stripping to create friction can undesirably cause increased wear, and moreover, such friction depends on the fit between separately manufactured parts and may thus be difficult to control.
In view of the failure of the prior art to provide a versatile support and lock assembly having the foregoing advantages and characteristics, and others which are inherent in the invention, it is an object of the invention to provide an improved sash support and lock assembly for tilt out or tilt-and take out window sash and their associated components.
Another object of the invention is to provide a lock assembly for the foregoing purpose which is adaptable, without significant change, for use with either the block and tackle or internal friction type true balance assembly or the simple spring balance assembly, without significant change to the lock assembly.
Still another object of the invention is to provide a lock for take out sash which permits the sash designer to specify a single type of jamb liner extrusion and to supply this as a component for use with the associated window sash, regardless of the type or style of balance specified.
Yet another object of the invention is to provide a window sash support and movement lock assembly, which includes a body having a pair of guide elements forming a part thereof, and in which at least one of the guide elements includes a tapered end face surface portion receiving a locking pin, and wherein the body is capable of being cammed into a spread-apart or extended position wherein the locking pin engages a part of an associated channel to secure the assembly against movement.
Another object of the invention is to provide a sash support and movement lock wherein an auxiliary friction adjustment device is provided so that the sliding friction of the assembly within the guide track may be controlled as desired.
Another object of the invention is to provide a sash support and movement block assembly which is easy to manufacture at low cost and which may be reliably assembled with minimum labor before use.
A still further object of the invention is to provide a sash support and movement lock assembly for a window sash wherein a unitary body of generally U-shaped cross section is provided and which body includes a cam-receiving opening, surfaces forming a part of that opening for engaging a rotary cam adapted to spread the body apart so that one portion of one of the guide elements forming a part of the body will approach and engage an associated channel to lock the assembly against vertical movement so the sash may be removed and replaced.
A further object of the invention is to provide a window sash support and movement lock assembly which is capable of use as both a left hand and a right hand part so as to reduce the number of parts required in inventory and user application.
Another object of the invention is to provide a sash support and movement lock assembly wherein the body and the cam cooperate in such a manner that only when the cam is in a locked position of the assembly may the window sash be removed.
Another object of the invention is to provide a movement lock and sash support assembly wherein the components are made from inexpensive materials but which has a very extended anticipated life in use.
A still further object of the invention is to provide a sash support and movement lock assembly which, without change, is adaptable for being supported by a sash cord forming a part of a balance assembly or by the hook of a balance spring only, which spring engaged a wire-formed spring holder in use.
The foregoing and other objects and advantages of the invention are achieved in practice by providing a sash support and movement lock assembly which includes a body having a structure connecting opposed guide elements, at least one of which carries a locking pin and which may be biased by a cam mechanism into engagement with one wall of the channel guiding the movement of the assembly in use, and in which the body moves between an extended or locked position tilted out and returns to a withdrawn position when the window sash is inserted and tilted to an upright position of use within an associated window jamb.
The manner in which the foregoing and other objects and advantages of the invention are achieved in practice will become more clearly apparent when reference is made to the following detailed description of the preferred embodiments of the invention set forth by way of example and shown in the accompanying drawings, in which like reference numbers indicate corresponding parts throughout.